Theoretical and Experimental Investigation of Coiled-Tubing Deformation Under Multiaxial Cyclic Loading

Zhao, Chaoying; Guijie, YU; Chi, Jianwei; Jiaxing, Zhang; Guo, Zhuang

doi:10.2118/191143-pa

Cited by 3 publications

(2 citation statements)

References 12 publications

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“…All of the limit curves in Figs. 7,8,9,10,11,12,13,14,15 show that the ∆P values for CT with a diameter increase are less than the ∆P values for CT without diameter growth. When a diameter increase is considered, the working limit of a CT pipe decreases.…”

Section: Resultsmentioning

confidence: 95%

“…The pipe may deform plastically if the stresses on the guiding arch and reel exceed the CT elastic yield strength 7 . Despite the fact that the internal pressure is smaller than the tubing’s yield strength, cyclic plastic bending and internal pressure cause CT diametral expansion and wall thinning 10 . CT suffers from low-cycle fatigue damage, and it occurs above the wellhead rather than in the well.…”

Section: Introductionmentioning

confidence: 99%

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Computational analysis of coiled tubing concerns during oil well intervention in the upper Assam basin, India

Neog

Sarmah

Baruah

2023

Sci Rep

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Coil tubing (CT) is widely regarded as one of the most effective servicing tools for dealing with a variety of oil and gas production issues, and it is also commonly used for oil well workover operations in India's upper Assam basin. The current work considers QT 800 to be the CT material used for actual oil well operations. With reference to actual operations carried out in some of the oil wells in the upper Assam basin, the current research analyses the limitations of CTs (QT 800, QT 900, and QT 1000) based on developing limit curves that can depict the operating limit and infer CT failure probability. This study also includes fatigue analysis to determine the likelihood of damage from hot oil circulation, water injection, and nitrogen shot operations while performing them using the CTs (QT 700, QT 800, QT 900, and QT 1000). The current work adopts the methodology of CT assessment based on a computational model built in MATLAB with respect to different oil well parameters in the upper Assam basin. This study takes an innovative approach by taking downhole temperature into account when determining the CT limit for QT 800, which signifies novelty in the current work. According to the computational analysis used in the study on CT limits, mechanical strain, thermal strain, and the combined strain of the CT material all affect CT elongation. This observation was often found to be a research gap in different research works as this aspect in previous studies was not considered while analysing CT operations. The findings of the present study highlight and draw the conclusion that temperature variations in the well and the CTU’s circulating fluid contribute linearly to CT strain. CT’s working limit diminishes with increasing internal and external pressure and diametrical growth, which eventually causes fatigue damage.

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Section: Resultsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Computational analysis of coiled tubing concerns during oil well intervention in the upper Assam basin, India

Neog

Sarmah

Baruah

2023

Sci Rep

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Simulation of ultra-low cycle fatigue cracking of coiled tubing steel based on cohesive zone model

Zhao

Zhong

Feng

et al. 2020

Engineering Fracture Mechanics

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Digital Solution for Coiled Tubing Pipe Pull Test Automation and Placement Optimization

Fonseca,

Armstrong,

Fossati

et al. 2024

Day 1 Tue, March 19, 2024

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A new coiled tubing (CT) pipe pull test placement optimizer and automation solution is developed and integrated into an autonomous CT unit. This method provides consistency in strategic and automated pull test placement to extend the life of the pipe and consequently reduce total cost of ownership and greenhouse (GHG) emissions. A case study in the North Sea showcases the solution in real-time operations and simulated cases demonstrate the potential impact. Pull tests are a common means of mitigating stuck pipe in CT operations. Traditionally, they are executed at fixed intervals while the CT is run in hole. Risks associated with this rote approach include repeated pull tests at an already fatigued section, which accelerates fatigue of the CT pipe, and pull tests executed in wellbore sections with completion restrictions. The new solution addresses those risks by systematically combining the pipe's fatigue profile, weld points, and completion information to strategically adjust the pull test schedule, reducing the impact of those tests on pipe fatigue and the risks associated with drifting across downhole completion jewelry. The pull test automation and optimization are integrated into an automation-enabled CT unit in the North Sea. The automation eliminates the human factor and the risk of repeating pull tests at the same locations on each run; it also minimizes pull tests at the weakest points, which include the weld points where cycle fatigue is accelerated, and it eliminates pull tests at restrictions, reducing the risk of abrading or damaging completion jewelry. Finally, besides standardizing pull test placement, the combination of the pull test optimization and automation frees the CT operator to focus on other critical elements of the operation such as running and monitoring the unit and downhole tools, managing the crew, and engaging the customer representative. The performance of the pull test automation and optimization solution is tested in a simulated environment to quantify the impact on the CT pipe from new (0% fatigue) to end of life (EOL, 100% fatigue). The simulation uses a CT pipe with 1 3/4-in. outer diameter (OD) and a mission profile from a previous intervention campaign. CT of this OD is common in CT operations worldwide, making it an interesting test subject for the analysis. As compared to the traditional pull test approach, the optimized pull test placement redistributes the fatigue to less-fatigued sections of the pipe and extends the useful life of the pipe from 137 runs to EOL to 176 runs to EOL. Extending the useful life by 28% is equivalent to reducing the pipe's run-on-run cost and GHG manufacturing emission contributions by 22%.

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Theoretical and Experimental Investigation of Coiled-Tubing Deformation Under Multiaxial Cyclic Loading

Cited by 3 publications

References 12 publications

Computational analysis of coiled tubing concerns during oil well intervention in the upper Assam basin, India

Computational analysis of coiled tubing concerns during oil well intervention in the upper Assam basin, India

Simulation of ultra-low cycle fatigue cracking of coiled tubing steel based on cohesive zone model

Digital Solution for Coiled Tubing Pipe Pull Test Automation and Placement Optimization

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